1. Field of Invention
The present invention relates to an accessory for use with bar clamps, and more specifically, to a bar clamp attachment for extending a bar clamp to a plurality of working lengths.
2. Background of the Prior Art
Bar clamps are well known to craftsmen for use in holding a work piece in a fixed position. Typically, a bar clamp is used to hold a workpiece comprising multiple objects together for gluing, welding, or other purposes where it is advantageous to temporarily retain the workpiece in a fixed position. When encountering a clamping task, a craftsman will assess the size of a workpiece and select a clamp suitable for its retention. In cases calling for a bar clamp application, a craftsman selects a clamp having an appropriate length to embrace the subject work piece. However, to accomplish a variety of clamping tasks in association with a variety of projects, a craftsman is required to have multiple clamps of varying lengths.
One example of a prior art bar clamp is disclosed in U.S. Pat. No. 4,926,722 issued to Sorensen et al. The Sorensen et al. bar clamp comprises a movable jaw, a bar, and a fixed jaw. A disadvantage of the clamps known in the art, such as the Sorensen et al. bar clamp, is the finite length of the clamping bar. For example, while a movable jaw provides a variety of clamping positions along the length of the clamping bar, the finite length of the clamping bar limits the range of clamping positions available for each clamp. The finite length of each bar clamp requires a craftsman to purchase multiple clamps of varying lengths to accommodate various workpieces in association with accomplishing a variety of clamping tasks.
Therefore, a longstanding need remains for improvements in bar clamping devices. Such improvements would provide a craftsman the capability of utilizing a movable jaw component and a fixed jaw component in conjunction with a variety of bar lengths to achieve a modifiable bar clamp of varying lengths.
An improved bar clamp extension attachment for extending the working length of a bar of a bar clamp to a plurality of working lengths is described comprising an extension bar that has transverse dimensions matching those of the bar of the bar clamp. The bar clamp extension of the present invention will extend the working length of a typical bar clamp that has a moveable jaw and a fixed jaw in slidable and fixed engagement, respectively, with the bar of the bar clamp. A plurality of projections or pins extend transversely from a first and second end of the extension bar. The pins engage a coupler at the first end for releasably joining the extension bar to the bar of the bar clamp at the end which held the fixed jaw, and engage the fixed jaw at the second end. In operation, the fixed jaw is removed from the bar of the bar clamp and attached to the second end of the extension bar. The first and second ends of the extension bar are interchangeable.
A coupler includes a receiving member that is generally U-shaped in transverse cross-section wherein the web section and leg sections are sized to closely accommodate the end portions of the bar of the bar clamp and the extension bar. The end portions of the bar and extension bar are placed in the receiving member with their pins aligned with corresponding recesses in the receiving member. The coupler or clamp also includes a cover plate with recesses that is placed over the bar and extension bar end portions with the recesses aligned with the pins at the end portions of the bar and extension bar. A central throughbore in the receiving member and cover plate receives a nut and bolt combination for securing the coupler to the end portions of the bar and extension bar. The extension bars pins are comprised of metal, or alternatively, are spring pins, roll pins, or dowels.
After the extension bar is connected to the bar clamp, the extended clamp functions in the same manner as the bar clamp prior to its modification. In operation, a workpiece is clamped between a movable jaw and a fixed jaw. Sqeezing a handle on the clamp advances the movable jaw along the bar until a desired pressure is applied to the workpiece. To open the clamp, a trigger is squeezed and the movable jaw is pulled and released from the workpiece.
These and other aspects of the present invention will become apparent to those skilled in the art upon reference to the following specification, drawings, and claims.